Cleaning up some compiler warnings

for a new version of rustc

rust_experiments/src/lib.rs

@@ -1,5 +1,5 @@
 
-#![feature(no_std, lang_items, const_fn, asm, core_str_ext)]
+#![feature(lang_items, const_fn, asm)]
 #![no_std]
 
 #[cfg(test)]
@@ -9,8 +9,6 @@ extern crate std;
 extern crate rlibc;
 extern crate multiboot2;
 
-use core::fmt::Write;
-
 /* externs */
 #[no_mangle]
 pub extern fn rust_setup_PIC() {
@@ -417,8 +415,15 @@ mod vga_buffer {
 
 #[cfg(not(test))]
 #[lang = "eh_personality"]
-extern fn eh_personality() {}
+#[no_mangle]
+pub extern "C" fn eh_personality() {}
 
 #[cfg(not(test))]
 #[lang = "panic_fmt"]
-extern fn panic_fmt() -> ! { loop {}}
+#[no_mangle]
+pub extern "C" fn panic_fmt() -> ! { loop {}}
+
+#[cfg(not(test))]
+#[lang = "eh_unwind_resume"]
+#[no_mangle]
+pub extern "C" fn eh_unwind_resume() { }